origin at the candle, we found that one part was condensable against a
cold spoon, or against a clean plate, or any other cold thing, and another
part was incondensable.

We will first take the condensable part, and examine it; and, strange to
say, we find that that part of the product is just water--nothing but
water. On the last occasion I spoke of it incidentally, merely saying that
water was produced among the condensable products of the candle; but
to-day I wish to draw your attention to water, that we may examine it
carefully, especially in relation to this subject, and also with respect
to its general existence on the surface of the globe.

Now, having previously arranged an experiment for the purpose of
condensing water from the products of the candle, my next point will be to
shew you this water; and perhaps one of the best means that I can adopt
for shewing its presence to so many at once, is to exhibit a very visible
action of water, and then to apply that test to what is collected as a
drop at the bottom of that vessel. I have here a chemical substance,
discovered by Sir Humphrey Davy, which has a very energetic action upon
water, which I shall use as a test of the presence of water. If I take a
little piece of it--it is called potassium, as coming from potash,--if I
take a little piece of it, and throw it into that basin, you see how it
shews the presence of water by lighting up and floating about, burning
with a violent flame. I am now going to take away the candle which has
been burning beneath the vessel containing ice and salt, and you see a
drop of water--a condensed product of the candle--hanging from under the
surface of the dish.

[Illustration: Fig. 11.]